SOG cuts the time to finish yes.

The idea is to grow many small plants close together so you grow from clones and only veg them for about 3 weeks. When you grow from seeds they need at least 30 day's to 45 day's to develop the antioxidants needed for a quality grow.

When you clone they inhered the age of the mother so you can veg them for less of a time and have smaller plants.

The time to finish flower is set by the genetics of the strain. Growing SOG you cut down on the veg time and that is how you grow faster. Now if you have enhanced CO² you can cut the flower time by 2 weeks on average.